Crushing devices, such as cone crushers, are typically used to crush rock, ore or minerals. Crushers may form a circuit of a process configured to crush material from a first size to a smaller size. After the material is crushed, the material may be moved to a grinding circuit for grinding the material to an even smaller size. Examples of crusher devices may be appreciated from U.S. Pat. Nos. 1,537,564, 4,192,472, 4,391,414, 4,478,373, 4,756,484, 4,844,362, 4,892,257, 4,895,311, 5,312,053, 5,372,318, 5,779,166, 5,810,269, 5,996,916, 6,000,648, 6,036,129, 6,213,418, 6,446,977, 6,648,255, 7,048,214 and U.S. Patent Application Publication Nos. 2003/0183706, 2005/0269436, 2006/0144979, 2008/0115978, and 2008/0272218.
A cone crusher typically breaks rock by squeezing the rock between an eccentrically gyrating spindle and an enclosing concave hopper. As rock enters the top of the cone crusher, it becomes wedged and squeezed between the mantle and the bowl liner or concave. Large pieces of ore or rock are broken and then fall to a lower position (because they are now smaller) where they are broken again. This process continues until the pieces are small enough to fall through a narrow opening at the bottom of the crusher.
The crusher head of cone crushers is typically guided by an eccentric assembly to actuate movement of the head for crushing material. A bushing is typically positioned between the crusher head and the eccentric assembly. A drive mechanism is often coupled to the eccentric assembly to drive movement of the eccentric assembly to move the crusher head to crush material. The bushing may include a flange that is integral to the bushing. The flange may have holes that permit bolts to pass through the holes to connect to the crusher head to ensure a very tight attachment between the bushing and the crusher head as may be appreciated from FIG. 13. The flanged bushing is typically composed of bronze.
Bushings are configured to provide a tight running fit between different components, such as the eccentric assembly and the crusher head. For instance, U.S. Pat. Nos. 5,413,756 and 5,730,258, both disclose bushings configured to provide a tight fit between different components to ensure the components are secured together, to provide a replaceable wear surface and to prevent other material from becoming positioned between the attached components.
Cone crushers often experience significant stress and strain as a result of crushing large rocks. Indeed, large variations in stress and strain experienced by the crusher head, shaft, and bushing of a cone crusher can be greatly increased when breaking up very large rocks. For instance, the crusher may be configured to crush rocks within a first size range. However, some rocks may enter the crusher that are much larger than this size range. The breaking of such relatively large rocks induces significant stress and strain on the crusher head, bushing and shaft. Significant additional stress and strain may also be introduced by attempting to crush an object that is not normally able to be crushed, such as a large steel ball or shovel tooth. The flange of the bushing can fail, or break, as a result of the stress and strain experienced by the shaft, bushing, and crusher head. The failure of the flange can also cause the bolts to become dislodged from the crusher. In some instances, the broken flange may become dislodge such that further operation of the crusher melts the flange or partially melts the flange, which can cause the crusher to seize. Such an occurrence can also cause other damage to the crusher and may result in significant down time that is needed for repairing the crusher.
A new crusher design is needed. Preferably, the new crusher design increases the stress and strain that a crusher may experience without experiencing a failure. The new design is also preferably configured to be easily implemented as an improvement on current designs of crusher devices to keep the cost of fabricating the new design of the crusher as low as possible.